Multiple sclerosis (MS) is a life-long chronic disease of the central nervous system that can cause symptoms of varying degree. MS occurs when myelin is lost in multiple areas in the central nervous system. More myelin is damaged with each attack, leading to progressive nerve deterioration. Myelin is a fatty tissue that surrounds and protects the nerve fibers. Myelin also greatly increases the speed and accuracy of nerve signal transmission. The loss of myelin forms scar tissue called sclerosis, also known as plaques or lesions. When damaged in this way, the nerves are unable to conduct electrical impulses to and from the brain. Communication between the brain and other parts of the body is disrupted. Causes There are many possible causes of MS, including viruses, autoimmune disorders, environmental factors, and genetic factors. MS affects mainly women between the ages of 20 and 50. Diagnosis With today's medicine, no definitive test is available to diagnose MS. But your doctor can make a probable diagnosis by following a careful process that demonstrates findings consistent with MS and that rule out other causes and diseases. In diagnosing MS, doctors use two criteria: There must have been two attacks at least one month apart. An attack is a sudden appearance of or worsening of any MS symptom or symptoms that lasts at least 24 hours. There must be more than one area of damage to the central nervous system myelin that must have occurred at more than one point in time and was not caused by any other disease. Evaluation and diagnosis of MS requires a variety of tools to rule out other possible nerve disorders and a series of laboratory tests that, if positive, confirms the diagnosis. Your doctor will start with a complete medical history and a neurological exam. The following may also help in the diagnosis of MS: Magnetic resonance imaging (MRI): a diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body to detect the presence of plaques or scarring caused by MS. Evoked potentials: procedures that record the brain's electrical response to visual, auditory, and sensory stimuli to show if there is a slowing of messages in the various parts of the brain. Cerebral spinal fluid analysis (also called spinal tap or lumbar puncture): a procedure used to make an evaluation or diagnosis by examining the fluid withdrawn from the spinal column to check for cellular and chemical abnormalities associated with MS. Blood tests: to rule out other causes for various neurological symptoms. Treatment There is no cure yet for MS. But you can take steps to ease symptoms and improve function and mobility. Your doctor may recommend the following to treat the conditions associated with MS: medication, assistive technology, and rehabilitation activities. Rehabilitation varies depending on the range, severity, and progression of symptoms.